645965563 has 2 divisors, whose sum is σ = 645965564. Its totient is φ = 645965562.

The previous prime is 645965533. The next prime is 645965587. The reversal of 645965563 is 365569546.

645965563 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645965563 is a prime.

It is not a weakly prime, because it can be changed into another prime (645965513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322982781 + 322982782.

It is an arithmetic number, because the mean of its divisors is an integer number (322982782).

Almost surely, 2^645965563 is an apocalyptic number.

645965563 is a deficient number, since it is larger than the sum of its proper divisors (1).

645965563 is an equidigital number, since it uses as much as digits as its factorization.

645965563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916000, while the sum is 49.

The square root of 645965563 is about 25415.8525924274. The cubic root of 645965563 is about 864.4431860355.

The spelling of 645965563 in words is "six hundred forty-five million, nine hundred sixty-five thousand, five hundred sixty-three".